Field
The disclosed concept pertains generally to microgrid systems, and, more particularly, to a microgrid system structured to detect overload conditions and take corrective actions relating thereto.
Background Information
A distributed power source is a small-scale power generation mechanism used to provide an alternative to or an enhancement of the traditional electric power system. Distributed power sources include, for example and without limitation, photovoltaic (PV) modules, wind turbine modules, backup generators, energy storage, and uninterruptible power supplies.
A microgrid is a discrete energy system consisting of a number of distributed energy sources and loads capable of operating in parallel with, or independently from, the main grid. When connected to the main grid, a microgrid will rely on a mix of power generation sources depending on the metric to be optimized (cost, greenhouse gas emissions, reliability). In the case where the microgrid is operating independently from the main grid (e.g., when the point of common coupling with the main grid has been be disconnected), the microgrid is typically said to be operating in an islanded mode.
Microgrids are desirable as the multiple dispersed generation sources of a microgrid and the ability to isolate the microgrid from a larger network generally provide highly reliable electric power. Typically, specialized hardware and software systems control the integration and management of the microgrid's components and the connection to the main grid.
Power distribution equipment and conductors in a microgrid can be subjected to overcurrent conditions where multiple sources are feeding into a shared/common bus, and/or where multiple loads may be present (or added). Currently, the busbars and conductors in a microgrid system are typically oversized to accommodate worst case conditions (maximum source current and maximum load). It would be advantageous to be able to coordinate the total current permitted on the common bus of a microgrid, as that would allow for optimizing the size (and cost) of the common bus conductors, as well as allow for new sources or loads to be plugged in or added over time at any power port on the microgrid system without concern for overload currents to become present on the common bus. This is of particular concern for a power flow topology that may evolve/change over time and allows for bidirectional power ports.